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Use of a low-loss header ?

There's a lot of articles about low-loss headers. What I can't figure out is whether or not a low-loss header has a place in a small single zone residential hydronic mod/con boiler heating system ? Seems that an installer can optimize the flow through the boiler, but requires a second circulator for controlling flow through heating zone. Seems like a considerable added expense, hence I'd like to know if there's any gains to be made in a small single zone heating system. My heating system has a large thermal mass with cast iron radiators and large gravity feed pipes.

You can always

build your own. Not as pretty, probably not as functional as a true LLH, but certainly less expensive. It's still primary secondary either way you look at it and there is no getting around the additional circulator.

It Depends

If the boiler manufacturer requires hydraulic separation because it has a high head heat exchanger (like a Gianonni), then you have to use a LLH or p/s piping.

If the boiler has a low head heat exchanger (like T.T., Lochinvar WHN, etc.), then you can probably get by using one circ if you do your calculations right. Follow the manufacturers instructions. The two that I mentioned show scenarios using one circ.

Bob Boan

​You can choose to do what you want, but you cannot choose the consequences. ​